Device and Method for Cooling and Dehumidifying Room Air

ABSTRACT

The invention relates to a device for cooling and dehumidifying air of a room, comprising a processing unit ( 7 ) that is embodied to process the coolant such that it is suitable for dehumidifying and/or cooling the air upon contact therewith, wherein cooling exceeding the cold due to evaporation can be achieved, a distribution unit ( 3 ), which is suitable for causing the coolant to flow past the air with direct contact, a collecting unit ( 5 ), which is suitable for feeding coolant that has flowed past the air back to the processing unit ( 7 ). The invention further relates to an associated method.

The invention relates to a device and method for cooling anddehumidifying room air.

For heating and cooling room air in buildings, primarily circulating airconditioners are known from the prior art. However, the operation ofthese devices is often associated with noise emission and drafts. As analternative, water-bearing cooling elements such as, e.g., coolingceilings have therefore also become established on the market. Incooling elements of this type, the cooling of the air of a room isachieved by the cooling elements being flowed through by a coolant andthus cooled. Heat is extracted from the air of a room and transferred tothe cooling element through thermal radiation and thermal conductionfrom the cooling elements to the ambient air. The heat is transportedaway from the cooling element by the coolant. However, cooling elementsof this type have a limited cooling capacity. The temperatures of thecooling elements may not be kept too low, so as to avoid a separation ofhumidity present in the air, which would lead to mold formation. Coolingelements of this type are not Cooling elements of this type are notsuitable for dehumidifying room air, either, since the separation of thehumidity present in the air should be avoided because of the dangersalready described of mold formation on the cooling element.

A cooling of air for a greenhouse is known from WO 06058959 A1. Warm airis thereby pumped past water that is sprayed. The heat of the air istransferred to the cooling water. A recirculation of air remainsnecessary to cool a room.

The object of the present invention is now to overcome the disadvantagesof the prior art and to disclose a device and a method for cooling anddehumidifying air, which avoids the noise emission and drafts ofrecirculating air conditioners as well as the capacity limitation andmold formation of cooling elements. This object is attained through thefeatures of the independent claims. Advantageous embodiments are foundin the dependent claims.

According to the invention it was recognized that a device for coolingand/or dehumidifying room air and containing the following componentsmust be created:

Firstly, a processing unit must be provided, which can process coolantsuch that it is suitable for dehumidifying and/or cooling air uponcontact therewith, wherein cooling exceeding the cold due to evaporationcan be achieved. Furthermore, a distribution unit is to be provided,which is suitable for causing the coolant to flow past the air withdirect contact with the air. Finally, a collecting unit is to beprovided, which is suitable for feeding coolant that has flowed past theair back to the processing unit. A device of this type makes it possiblefor the room air in direct contact with the coolant to be cooled and/ordehumidified. In particular it is desirable to cool and to dehumidifythe air simultaneously. It is known from the prior art to cool the airof a room with coolant that flows by the air with direct contact; forinstance, fountains with which a cooling is achieved are often installedin cafes. The water is usually recirculated hereby and heated by longeroperation of the fountain. A cooling effect is also achieved byevaporation, but, particularly with humid weather conditions, noincrease in comfort is thereby achieved, since although theuncomfortably high temperatures can be somewhat reduced, the airhumidity is increased due to evaporation. A cooling exceeding the coldfrom evaporation would be conceivable, e.g., through the constant use ofcooler fresh water, but it would be uneconomical, since it would lead toan unjustifiably high requirement for fresh water. Not until theinteraction of the processing unit, distribution unit and collectingunit provided according to the invention has it been possible to producea device with which room air can be cooled without humidification whileat the same time forming a coolant circulation in which at most smallamounts of coolant need to be replenished. Distribution unit, processingunit and collecting unit can be structurally combined thereby. Inparticular the distribution unit can also contain the collecting unit.It is also possible for the collecting unit not to feed the coolantdirectly to the processing unit, but first to another distribution unit.A cooling known from the prior art can also be carried out exclusivelyby cold due to evaporation with the device according to the inventionfor cooling without humidification, depending on the mode of operation.However, the device differs in that a cooling that exceeds cold due toevaporation is possible. The cooling exceeding the cold due toevaporation is achieved by heat being transferred from the air to thecoolant, which thereby increases its sensible heat, that is, absorbsheat by increasing the temperature. Comfort can be improved, even ifpart of the cooling is carried out by cold due to evaporation and thehumidification of the air during cooling is only reduced and notavoided. Although different coolants are conceivable, above all waterand mixtures containing water are suitable as a coolant.

Air conditioners are likewise known in which room air bubbles throughcooled water or is sprayed therewith (so-called air washers); however,there the air is removed from the room with the aid of blowers andsubsequently returned thereto. Consequently, there are the same problemshere (e.g., noise emission, drafts), as with conventional airconditioners. This is precisely not the case according to the invention.Furthermore, with air conditioners of this type the cooling throughradiation cannot be used, since the cool coolant cannot absorb anyradiation from the room to be cooled. With the present invention it ispossible to additionally use the radiation cooling of the coolant.

It should be made clear at this point that the term “room” of courseprimarily means rooms in buildings. However, the term “room” should betaken to have a broad meaning. It covers any area where people are,whose comfort is to be increased. It therefore also includes passengercompartments in vehicles and aircraft. The decisive factor is that theair is processed in the area, i.e., the distribution unit is locatedwhere people may be, whose comfort is to be increased. Air is thereforenot processed in a separate unit and then pumped into this area. Ofcourse, the term “air” should not be narrowly interpreted; for instance,special gas mixtures for the ventilation of rooms that can containmoisture, are also covered by this term.

A suitable distribution unit for the coolant is a fountain installed inthe room. This can be designed in an optically appealing manner.Commercially available components can also be used hereby, sincefountains in rooms are definitely known.

It is likewise conceivable for the distribution unit to be a wall orroom unit on which a thin liquid film can flow past or flows past. Witha thin liquid film it is possible to create a large surface of coolantflowing past. It permits an efficient cooling or dehumidification.

One way of realizing the distribution unit is to arrange coolant grooveson or under the floor or the ceiling (with corresponding air openings)of the room. A space-saving device is thus created that is not verynoticeable.

The processing unit is preferably a cooler for the coolant, since anadequate cooling makes it possible for the coolant when flowing past airto cool it without humidifying it. Coolers of this type are adequatelyknown in the prior art and can be obtained at a reasonable cost. Thereare also coolers that operate in an energy-efficient manner, the runningcosts of which are kept within a limited range. When the cooled coolantflows past the air to be cooled, if necessary moisture is removed fromthe air. This water that additionally reaches the cooling circuit doesnot present any problems at all, since in general the coolant isprimarily composed of water anyway. If necessary, suitable overflowcontainers or outlets are to be provided in the system.

A further or additional way of realizing the processing unit is to addadditives that reduce the vapor pressure of the coolant. If, forexample, water is used as a coolant, the vapor pressure can be reduced,e.g., through the addition of substances (e.g., salts) with acorrespondingly hygroscopic action. A similar effect can also beachieved by adding a liquid to water. Substances that are miscible withwater can thereby be added, whereby a solution is produced, the vaporpressure of which can be lower than that of pure water. Likewisesubstances that are not miscible with water can be added. The loweringof the surface can lead here to a reduction of the vapor pressure. Thismeans that, even at higher temperatures of the coolant, the evaporationof the water can be reduced so far that the condensation of the indoorair humidity on the surface of the coolant predominates and no moistureis transferred to the room air. In fact, moisture is removed from theroom air. The concentration of the added substances (e.g., hygroscopicsalts) that reduce the vapor pressure is thereby reduced so that aregeneration of the coolant must take place. These substances can beadded again in the processing unit. However, for continuous operation itis in particular expedient to expel water absorbed by the coolant in theprocessing unit, e.g. by evaporation or ice crystal formation, thusreestablishing the original concentration of the additions. Admittedly,this is associated with a certain energy expenditure. For evaporation,the coolant must be either heated or exposed to a lower ambientpressure. For the regeneration of the coolant through ice crystalformation, it must be cooled further below this and the ice skimmed off.However, these measures can also take place in a side stream thatsubsequently is mixed with the main stream again.

A stable and quiet flow is achieved if additives that avoid turbulencesin the flow are added to the coolant. If water is used as the coolant,long-chain polymers are suitable for laminarizing the flow. Suchadditives suppress the formation of microeddies and thus produce alow-friction and low-noise laminar flow, even with higher Reynoldsnumbers.

Irrespective of additives that avoid turbulences in the flow, additiveswith a biocide action are also conceivable. This means hygiene problemscan be avoided. For increased acceptance of the device according to theinvention, suitable odor-active substances can also be added to thecoolant. The addition of other substances to increase the capacity ofthe coolant to absorb contaminants in the room air is also conceivable.

The sketch according to FIG. 1 is designed to explain an exemplaryembodiment. Water is guided with the pump 1 through the feed line 2 to ahorizontal pipe 3, which has an aperture slot on the underside. Thewater flows out through this aperture slot as a water film 4. Acollecting tank 5 is attached below, from which the water is pumped backto the pump 1 through the drain line 6. The water is pumped again fromthe pump 1 to the feed line 2, during which it is cooled again in thecooler 7 arranged after the pump 2.

1. Device for cooling and dehumidifying the air of a room in whichpeople may be, comprising a processing unit (7), which is embodied toprocess the coolant such that it is suitable for dehumidifying and/orcooling the air upon contact therewith, wherein cooling exceeding thecold due to evaporation can be achieved, a distribution unit (3), whichis suitable for causing the coolant to flow past the air in the roomwith direct contact, a collecting unit (5), which is suitable forfeeding coolant that has flowed past the air back to the processingunit.
 2. Device according to claim 1, characterized in that thedistribution unit (3) is or contains a device in the manner of afountain installed in the room.
 3. Device according to claim 1,characterized in that the distribution unit (3) is a wall or room unitor contains a wall or room unit, on which a thin liquid film can flowpast or flows past.
 4. Device according to claim 1, characterized inthat the distribution unit (3) is embodied in the form of coolantgrooves on or under the floor and/or the ceiling of the room or containssuch cooling grooves.
 5. Device according to claim 1, characterized inthat the distribution unit (3) is a cooling device installed in a roomand having at least one opening for the air to be processed, in which aliquid film (4) can flow or flows.
 6. Device according to claim 1,characterized in that the processing unit (7) is a cooler for thecoolant.
 7. Device according to claim 1, characterized in that theprocessing unit (7) is embodied such that the concentration of additivesthat reduce the vapor pressure of the coolant can be increased. 8.Device according to claim 1, characterized in that the coolant containsadditives that avoid turbulences in the flow.
 9. Device according toclaim 1, characterized in that the coolant contains additives that canbind contaminants or odors in the room air.
 10. Method for coolingand/or dehumidifying air in a room, containing the following steps:Processing the coolant such that it is suitable for dehumidifying and/orcooling the air upon contact therewith, wherein cooling exceeding thecold due to evaporation occurs; Distribution of the coolant in a room inwhich people may be, so that the coolant flows past the air with directcontact; Collection of the coolant that has flowed past the air forprocessing again, so that a cooling circuit is produced.